In U.S. Pat. No. 3,315,025 to Tomlinson, the disclosures of which are incorporated herein by reference, there have been described cables for the transmission of high-frequency signals, particularly television signals and characterized by having expanded insulations and an outer metal tape coated with an adhesive that bonds the tape to a heavy polymeric jacket and also bonds together an overlapping longitudinal seam in the tape itself. Although the thickness of the adhesive is very low, not exceeding 0.002 inch, it does constitute a hiatus between the metallic portions of the tape. This hiatus acts as a window in the shielding afforded by the tape in that it permits leakage of some radiation from the cable. This leakage increases with frequency. In an application by W. L. Grey, S.N. 134,560 now U.S. Pat. 3,662,090, assigned to the assignee of the present invention, means have been suggested of folding the conductor tape or omitting a strip of its adhesive, so as to provide metal-to-metal contact within the area of the overlapped seam. These means are, however, costly of execution, and a simpler, less expensive means of closing the window in the cable shielding has now been discovered.